Apparatus for producing charged particles

Abstract

In a pair of surface-shaped silent discharge electrodes opposed to each other and separated by a predetermined space therebetween, phases of alternating voltages are applied to said respective silent discharge electrodes shifted in phase with respect to each other so that a silent discharge may arise alternately on either one of the electrode surfaces. A second alternating voltage is applied between the silent discharge electrodes and is alternatingly varied at a fundamented frequency twice as high as the frequency of the first alternating voltages applied to said surface-shaped silent discharge electrodes and is not inverted in polarity during the period when the silent discharge exists on either one of the electrode surfaces. Powder particles are passed through the space which separates the pair of surface-shaped silent discharge electrodes and charged in either positive or negative polarity continuously at a high efficiency.

What is claimed is: 
     
       1. An apparatus for producing charged particles, comprising a pair of surface-shaped ion generating electrodes, in each of which every other one of parallel linear electrodes spaced apart at a predetermined interval are connected in common to form separate electrode groups, said parallel linear electrodes, of at least one said electrode group being coated with an insulator, and an alternating voltage is applied between said respective electrode groups, and an alternating voltage is applied between said respective electrodes; a charging space formed between said pair of ion generating electrodes spaced in opposition to each other; means for shifting the phases of the alternating voltages applied to the respective ion generating electrodes relative to each other; and voltage supply means for applying between said respective ion generating electrodes another alternating voltage having a fundamental frequency twice as high as the frequency of the alternating voltage applied to the respective ion generating electrodes in such phase relationship to said latter alternating voltage that inversion of the relative voltage between said respective electrode surfaces may not occur during the period when silent discharge is arising on one of the electrode surfaces. 
     
     
       2. An apparatus for producing charged particles, in which there are provided a pair of surface-shaped silent discharge electrodes with a space interposed therebetween and a high voltage is applied across said pair of surface-shaped silent discharge electrodes, comprising: a. a plurality of electrodes arrayed in parallel to each other and insulated from each other to form each said surface-shaped silent discharged electrode,   b. an A.C. voltage supply for establishing an uneven alternating electric field between adjacent electrodes among said plurality of electrodes,   c. means for shifting the relative phase between the A.C. voltage supply for one of said surface-shaped silent discharge electrodes and the other A.C. voltage supply for the other of said surface-shaped silent discharge electrodes, provided between said A.C. voltage supplies, and   d. means for applying a high voltage between said plurality of electrodes forming one of said surface-shaped silent discharge electrodes and said plurality of electrodes forming the other of said surface shaped silent discharge electrodes, the frequency of said high voltage being twice as high as the frequency of the A.C. voltage supply for etablishing an uneven alternating electric field between said adjacent electrodes.   
     
     
       3. An apparatus for producing charged particles as claimed in claim 2, in which each said surface-shaped silent discharge electrode consists of a plurality of linear electrodes arrayed in parallel to each other. 
     
     
       4. An apparatus for producing charged particles as claimed in claim 2, in which said plurality of electrodes are embedded within a single planar insulator layer. 
     
     
       5. An apparatus for producing charged particles as claimed in claim 2, in which among said plurality of electrodes only one of the electrodes adjacent to each other is coated by an insulator. 
     
     
       6. An apparatus for producing charged particles as claimed in claim 2, in which each said surface-shaped silent discharge electrode comprises a single planar electrode and a grid-like electrode consisting of a plurality linear electrodes arrayed in parallel to each other, said planar electrode and said grid-like electrode being positioned as opposed to each other. 
     
     
       7. An apparatus for producing charged particles as claimed in claim 2, characterized in that each said surface-shaped silent discharge electrode consists of a plurality of linear electrodes arrayed in parallel to each other along an outer plane surface of a single insulator layer and also along an inner plane surface of said insulator layer itself. 
     
     
       8. An apparatus for producing charged particles as claimed in claim 2, characterized in that each said surface-shaped silent discharge electrode consists of a plurality of parallel linear electrodes arrayed along each of two plane surfaces disposed in parallel to each other within a single planar insulator layer itself. 
     
     
       9. An apparatus for producing charged particles as claimed in claim 2, characterized in that said pair of surface-shaped silent discharge electrodes are formed in two cylindrical shapes disposed in a concentric relationship. 
     
     
       10. An apparatus for producing charged particles as claimed in claim 2, characterized in that said pair of surface-shaped silent discharge electrodes are formed in two conical shapes disposed in a concentric relationship. 
     
     
       11. An apparatus for producing charged particles, comprising a pair of surface-shaped ion generating electrodes in each of which there are provided a grid electrode consisting of parallel linear electrodes spaced apart at a predetermined interval and a surface-shaped electrode spaced apart from said grid electrode at a substantially fixed distance and insulated by an insulator, and an alternating voltage is applied between said respective electrodes; a charging space formed between said pair of ion generating electrodes spaced in opposition to each other; means for shifting the phases of the alternating voltages applied to the respective ion generating electrodes relative to each other; and voltage supply means for applying between said respective ion generating electrodes another alternating voltage having a fundamental frequency twice as high as the frequency of the alternating voltage applied to the respective ion generating electrodes in such phase relationship to said latter alternating voltage that inversion of the relative voltage between said respective electrode surfaces may not occur during the period when silent discharge is arising on one of the electrode surfaces.